I have not been able to perform any research on part numbers yet because bmwfans.info and realoem.com do not have any info on the 335xi. I'll see if I can elicit some help from our friendly parts department to pull up a list of brake parts for an I and XI so I can compare notes.

are you certain that the 355mm, 6 pistons will not fit 17 inch wheels?
some people said a spacer might help... awaiting advices.

I've looked extensively into the 6-piston 355mm Brembos. They're not going to fit 17" rims. The dimension from the center of the wheel to the outer edge of the caliper is 210mm (8.26"). They won't clear my 18" Advan RS wheels (there is no spacer needed, the barrel dimension is what won't clear). The 4-piston 355mm system is 200mm (7.87").

I talked to the guys at AP Racing for a little bit with regards to BBK setups on the XI. They think that the regular I setup should work for us.

I have not attempted anything yet coz my car is still in the shop. However, with my vacation coming up, I might plunge into some uncharted water and see if I'll come out alive.

BBKs should work with the non-XI and XI models without a problem. It's pretty much the matter of the wheel size and clearance. Contact me via PM or e-mail (James************.com). We've got the best deals on all Brembo, Stoptech, and AP Racing BB kits.

BBKs should work with the non-XI and XI models without a problem. It's pretty much the matter of the wheel size and clearance. Contact me via PM or e-mail (James************.com). We've got the best deals on all Brembo, Stoptech, and AP Racing BB kits.

That's a bold statement even Brembo won't dare to make. Are you going to issue a FULL refund (i.e. no restocking charge), if one of us ordered the regular i BBK and it won't fit our cars?